Making and installing a collector plate assembly

ABSTRACT

A method of fabricating an industrial electrostatic precipitator comprising the steps of forming a complete collector plate assembly outside of the precipitator gas box, and lowering the collector plate assembly as a unit into the box until the assembly comes to rest on a framework previously built into the box.

United States Patent lnventors Philip L. Van Hufiel 5 References Cited Detroit; Harold J. Raines, Pleasant Ridge; Clement UNITED STATES PATENTS I Martzom, Detroit 8 of Mich 2,642,952 6/1953 Landgraf 29/462 X AppL No 9 1 2 3,483,670 12/1969 Qumtllran et al 55/[47 X Oct 24, 3,1 Steurnagel X Patented Jan. 11, 1972 Primary Examiner-John F. Campbell Assignee American Standard Inc. Assistant Examiner-Donald P. Rooney New York, N.Y. Attorneys-John E. McRae, Tennes l. Erstad and Robert G. Crooks MAKING AND INSTALLING A COLLECTOR PLATE ASSEMBLY 9 Claims, 14 Drawing Figs.

[1.8. CI 29/157 1R,

29/462, 29/469, 55/142, 55/147, 55/148, 55/154, ABSTRACT: A method of fabricating an industrial electro- 55/151 static precipitator comprising the steps of forming a complete Int. Cl B2ld 53/00, collector plate assembly outside of the precipitator gas box, B2lk 29/O0,B23p 15/26 and lowering the collector plate assembly as a unit into the Field Of Search 29/157 R, box until the assembly comes to rest on a framework previ- 462, 469; 55/141, 142, 147, 148, 151 ously built into the box.

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HAROLD Amlvis PHILLIP MM Harm PATENTEU-Jm 1 B72 SHEET 3 0F 4 FIG-LU IN VENTORS CLEMENT L. flnrzozori H4201. a PAM/5 PHILLIP KM Hui/6L MAKING AND INSTALLING A COLLECTOR PLATE ASSEMBLY GENERAL BACKGROUND Conventional electrostatic precipitators utilize a great number of comparatively large and heavy collector plates. For example, each collector plate may be on the order of 6 feet long and 27 feet high; such a collector plate might weigh about 400 pounds. Commonly each collector plate is individually suspended from an overhead framework within the gas box. Under conventional fabrication procedures the overhead framework is constructed inside the box before the individual collector plates are introduced to the box. The plates may be lowered into the box prior to installation of the box top wall, and prior to introduction of the ionizer wires mechanisms.

The installation of each collector plate 28 may be accomplished by lifting each plate above the level of the box, swinging the plate in a horizontal arc over the box, and lowering the collector plate into the box such that it is suspended from the aforementioned framework; in some cases it may be necessary to insert the plates from below the box, as by moving them up through an opening in the box bottom. The general operations of lifting, swinging and lowering may be performed with a mobile crane having a suitable length boom. After installation, each plate must be aligned or adjusted with the adjacent plates and with the intervening ionizer wires. In some instances the time required to install and align each collector plate averages out to more than 1 hour, due to the fact that each plate must be individually unloaded, lifted, lowered, shimmed, and welded to the support framework and to the adjacent collector plate tie members.

The present invention seeks to reduce the total time required to position and install a set of collector plates in a precipitator gas box. In general this time reduction may be accomplished by forming a complete collector plate assembly outside the gas box, and moving the entire assembly into the box, as by lifting the entire assembly above the level of the box, and lowering the assembly as a single module into the box until the assembly is supported by the load-bearing framework.

The fabrication of the collector plate assembly is preferably accomplished in a factory remote from the area where the gas box is to be erected. By this fabricating the entire collector plate assembly in the factory it is possible to utilize various aligning jigs, fixtures, drills, automatic welders, etc. for more rapidly carrying out the assembly operations and for achieving better and more consistent alignment of the collector plates. Such uniform alignment or spacing of the collector plates is a desired goal, since the dust collection efficiency of the precipitator is related to the wire plate spacing. If the wire plate spacing is too far at some points some of the dust will not be attracted to the plates at those points; if the wire plate spacing is too small at some points there will be sparking from the wires to the plates at those points and a drop in the applied voltage, with consequent lessening of ionization and dust collection.

Preferably the collector plate module is designed so that the individual plates are tied together in true parallelism; however the plates are collectively swingable so that during service the entire module acts as a single massive pendulum to thus seek a position wherein all of the plates take true vertical orientations. The swingable nature of the assembly is advantageous also during the transport stage (factory to site) in that it permits each module to be collapsed into a relatively small rattlefree bundle capable of withstanding jars ans shocks commonly occurring during highway or rail car transport operations.

THE DRAWINGS FIG. I is a sectional view taken through a conventional electrostatic precipitator.

FIG. 2 is a perspective view of a collector plate assembly formed according to the invention.

FIG. 3 through 8 are fragmentary sectional views illustrating structural details utilized in the FIG. 2 assembly.

FIGS. 9 and 10 show the FIG. 2 assembly collapsed for shipment.

FIG. I] shows a structural detail utilized in the FIG. 12 form of the invention.

FIGS. I2 and 13 are views showing an alternate to the FIG. 2 construction. FIG. 12 shows the unit installed. FIG. 13 shows the unit collapsed for shipment.

FIG. 14 shows a structural detail which can be used in lieu of the construction feature of FIG. 3.

FIG. I

FIG. 1 illustrates an electrostatic precipitator which includes a rectangular gas box 10 having a front wall 12, top wall 14, two unnumbered sidewalls, and a dust hopper l6. Disposed within the upper portion of the gas box I0 is a rectangular metallic frame 18 which serves to suspend the ionizer wires 20. Each ionizer wire is held taut by means of a milk bottle weight 22.

High voltage on the order of 40 kv is supplied to the ionizer frame 18 and wires 20 by means of two metallic electrodes 24, only one of which is visible in FIG. 1. As shown in FIG. 1, the electrode has its lower end connected to a frame super structure 26 which extends normal to the plane of the paper to interconnect the various wire support bars 27 running parallel to the plane of the paper. The general arrangement involves an overhead mechanism for suspending a plurality of rows of ionizer wires 20. The twelve wires shown in FIG. I constitute one row; there may in practice be seven or more rows of wires, making a total of 84 or more wires. Larger collectors might contain hundreds of such wires.

Adjacent rows of wires may be spaced about 9 inches apart, the space between the rows of wires being occupied by the dust collector plates 28, each plate having a frontal edge 30, an upper edge 32, a rear edge 34, and a lower edge 36. FIG. I shows only two collector plates. In practice additional plates are provided in accordance with the number of rows of ionizer wires, the general arrangement being such that each row of wires is located midway between two adjacent collector plates. In an illustrative example there might be two collector plate assemblies, each containing eight collector plates.

As shown in FIG. I, the dusty gas enters the collector through an inlet opening 38 in the gas box front wall 12; it then flows in parallel slices between the collector plates. Dust particles in the dusty gas stream are ionized by the wires 20 and are attracted to the grounded collector plates 28. Periodically the plates are rapped or hammered by pneumatic or electric devices (not shown) to discharge the collected dust into hopper 16. The clean gas flows on a continuous basis through the collector in the direction denoted by arrows 40.

FIG. 2

FIG. 2 illustrates a collector plate assembly or module which may be manufactured outside a gas box under the theory of the present invention. The assembly comprises a set of upper tie bars 42 and a set of lower tie bars 44, all four of said tie bars extending transversely across the six collector plates 28. The upper tie bars are of I-beam cross section as shown in FIG. 3. Each end of each upper tie bar has welded thereto a short angle section or foot 46, the purpose of which is to support the I-beam on a frame element located in the gas box. FIG. 2 shows in phantom lines two of the gas box frame elements 48. These frame elements can extend parallel to the collector plates as shown in FIG. 2 or transversely across the collector plates as shown in FIGS. 11 and 12. Elements 48 are installed in the gas box before the collector plate module is lowered into place.

FIGS. 3 and 7 illustrate the general manner of attaching each collector plate to the upper tie bars 42. Each collector plate is welded at its upper edge to the flanges 29 and 31 of a tubular reinforcement 33. The tubular reinforcement rigidities the upper portion of the collector plate and tends to keep the plate from bending or warping in the vertical plane. As shown in FIG. 3, the tubular reinforcement 33 extends beyond the front edge 30 of the collector plate and through a circular opening in the web of the tie bar 42. The extending portion of reinforcement 33 has a rotary fit in the tie bar opening so that the collector plate can swing or pivot about the tube 33 axis. Washers 35 may be welded to the tubular reinforcement at points adjacent opposite faces of the tie bar to prevent play or movement of the collector plate in the arrow 37 directions. The joint shown in FIGS. 3 and 7 may be duplicated at each tie bar 42.

The configuration of the collector plate 38 may be conventional, i.e., the plate may be flanged at its front and rear edges and also at intermediate points to form vertical pockets or channels for better retention of the collected dust. FIG. 5 shows one conventional method of flanging the collector plate at its front edge. As there shown, the collector plate is bent into a generally triangular cross section comprised of a first leg 50, a second front web 52, and a third leg 54. The triangular cross section extends the entire vertical dimension of the plate. A similar cross section may be provided at the rear edge 34 of each collector plate.

FIGS. 6 and 8 illustrate one way that each collector plate can be connected to the lower tie bars 44. As shown in FIG. 8, the lower edge of the collector plate is welded to the flanges 49 and 51 of a tubular reinforcement element 53. As seen in FIG. 6 the tubular reinforcement portion 53 extends forwardly through a circular opening in the tie bar 44. A washer 55 may be welded or otherwise secured to reinforcement 53 to retain the tie bar on the reinforcement. Preferably the tubular reinforcement has a rotary fit within the opening in bar 44 for allowing the collector plate to swing about the reinforcement 53 axis.

FIG. 5

FIG. 5 illustrates one way of attaching a spacer bar 58 to the front and/or rear edge of each collector plate 38 midway between its upper and lower edges. Bar 58 functions as a spacer device for minimizing any tendency of the plates to weave or vibrate in response to gas pressure forces and electrical forces. The bar 58 does not take any vertical load, and it can be attached to the collector plates by means of simple spring clips 60 having swivel connections 62 with the bar. Such swivel connections let the spring clip undergo some rotary adjustment and thus obviate the need for precisely aligning the clip parallel to the bar edges.

TRANSPORTING THE FIG. 2 ASSEMBLY The FIG. 2 assembly (exclusive of the I-beams 48, and tie bars 44 and 58) is preferably assembled or fabricated in a factory remote from the location of the gas box. The assembly presents a relatively bulky structure which could under some circumstances be difficult to brace and ship from the factory to the field site. Thus, assuming an assembly having a collector plate spacing of 9 inches, an eight plate collector might have a transverse width of approximately 70 inches, 2 height of perhaps 27 feet and a depth of 6 feet. Such a package would be difficult to ship by truck or by rail car without standing the plates on edge. If the plates were thus laid on edge they could warp or twist in response to the jarring movements commonly occuring during starting or stopping of trucks and flat cars. To minimize such transit damage and to provide a compact shipping bundle it is proposed to collapse the collector plate assembly, and to interleave the collector plates of two assemblies together as shown generally in FIGS. 9 and 10.

FIG. 9 shows two separate collector plate assemblies, each comprising two upper tie bars 42 and seven collector plates. Each collector plate is pivotally attached to its tie bar, as at 33. Therefore the collector plates of one assembly can be interleaved with the plates of the second assembly such that plates of one are interposed between the plates of the other. The flange areas 52 at the front and rear edges of the collector plates are offset or staggered as shown in FIG. 10 so that the plates in one assembly are in substantial engagement with flange areas of the other assembly, thereby providing a rattlefree bundle. The intermediate flanges 64 on the plates of one assembly may also be substantially in engagement with plate areas of the other assembly to preclude rattle or bending of the plates during transit. If desired, wodden filler blocks may be interposed between the face areas of the plates as further protection against rattle or warping. Flexible straps may be trained around the bundle at points along the bundle length to keep the bundle together.

INSTALLATION OF THE FIG. 2 COLLECTOR ASSEMBLY At the job location the two collector plate assemblies of FIG. 9 may be drawn apart to separate one from the other. Thereafter each collector plate assembly may be hoisted upwardly to the upright condition of FIG. 2. At this time the lower tie bars 44 and the intermediate tie bars may be attached to the assembly, and the assembly hoisted above the level of the gas box, then swung over the gas box, and lowered into the box interior.

The assembly may be supported within the gas box by any of several suitable frame mechanisms, one of which is illustratively shown in FIGS. 2 and 4. The FIG. 2 support framework comprises two parallel I-beams 48. Enlarged openings 66 (FIG. 4) may be formed at spaced points along each I-beam for reception of the nut-bolt assemblies 68. The general procedure involves merely a lowering of the collector plate assembly until the flanged feet 46 rest on the I-beams 48, at which time the nut-bolt assemblies 68 may be attached as shown in FIG. 4 to anchor the collector plate assembly at its four corners. Openings 66 are preferably enlarged in lateral directions to accommodate variations in I-beam spacing and hole spacing which are commonly encountered in field erection work. Other arrangements than that shown in FIG. 4 can be employed to mount the collector plate assembly on the supporting framework 48.

FIG. 11 illustrates one alternate mounting arrangement that can be employed instead of the FIG. 4 mounting scheme. In the FIG. 1] arrangement each supporting [beam 48' is oriented transverse to the collector plates. FIG. 12 shows one of the I-beams in side elevation.

The FIG. 11 arrangement comprises a saddle member 70 suitably riveted or otherwise secured to the I-beam 48' at a location where it will underlie one of the feet 46. Each of the tie bar feet 46 may be provided with a headed guide pin 72 going through a compression spring 74, said spring being retained between the lower face of the foot 46 and a washer 76; the washer is suitably trapped on pin 72 by means of an E-ring 78.

The operation of installing the FIG. 12 collector plate module involves a lowering of the module until the various pins 72 enter the enlarged openings 80 in saddles 70. The springs 74 thereupon bear the weight of the collector plate assembly.

FIG. 13

It is believed that each collector plate assembly can be individually shipped in the compacted collapsed mode shown in FIG. 13. In this arrangement the tie bars 44 can be attached to the collector plates at the factory, and each collector plate assembly can be collapsed or pivoted for transport to the site. Wooden filler clocks may be interposed between the collector plates to protect against plate warpage during shipment.

FIG. 14

FIG. 14 illustrates a structural variation which can be used instead of the structure shown in FIG. 3. As shown in FIG. 14, the tubularreinforcement 33 is provided with a headed pin 82 which is rotatable in an opening in tie bar 42. The pin is welded or otherwise fixedly secured to the reinforcement 33 to form a part of the reinforcement structure.

The specific improvement comprehended by this invention is the concept of forming a collector plate assembly at a factory, shipping the assembly to the job site in a compact rattlefree mode, and installing the assembly as a single module within the gas box. This method of manufacture and erection should reduce overall assembly time and should provide a more uniform spacing of the collector plates then is attainable under conventional erection practice wherein the collector plates are individually installed and aligned in the gas box.

We claim:

1. In the method of fabricating an electrostatic precipitator of the type which includes a gas box, vertical rows of ionizer wires within the box, and vertical collector plates interposed between the rows of wires: the improvement comprising the steps of tying the collector plates together in a bundle outside the box, said typing step including the substep of forming pivotal connections between each collector plate and tie bars spanning the upper and lower ends of the plates; collapsing the bundle by swinging the plates toward one another around the aforementioned pivotal connections; transporting the collapsed bundle from the bundle-manufacturing point to the gas box location; uncollapsing the bundle; and moving the bundle into a suspended position within the box such that the plates hang vertically in spaced parallelism with one another.

2. The method of claim 1 and further comprising the step of installing the ionizer wires in the box after the collector plates are in place.

3. The method of claim 1 wherein the step of moving the bundle into the gas box includes the substep of lowering the bundle through the roof of the gas box.

4. In the method of fabricating an electrostatic precipitator of the type which includes a load-bearing framework within the upper area of a gas box, spaced parallel collector plates suspended from the framework, and vertical rows of ionizer wires between the plates: the improvement comprising the steps of pivotally attaching two spaced tie bars to the upper ends of the collector plates while the plates are outside the gas box; swinging the plates around the aforementioned pivotal connections such that the plates are collapsed together in a compact bundle; transporting the bundle from a manufacturing station to the gas box location; and subsequently moving the bundle into the gas box to a position such that the upper tie bars are supported by the load-bearing framework.

5. The method of claim 4 and further comprising the substeps of forming a tubular reinforcement along the upper edge of each collector plate, forming holes at spaced points along each upper tie bar, and locating end portions of the reinforcements in the tie bar holes whereby the upper tie bars are pivotally attached to the plates.

6. The method of claim 4 and further comprising the step of pivotally attaching two additional tie bars to the lower ends of the collector plates while the plates are outside the gas box; said last-mentioned step including the substeps of forming a tubular reinforcement along the lower edge of each collector plate, forming holes at spaced points along each lower tie bar, and locating end portions of the reinforcements in the lower tie bar holes so that said lower bars become pivotally attached to the plates.

7. A method of fabricating an electrostatic precipitator of the type which includes a load-bearing framework within the upper area of a gas box, and collector plates handing from said framework in general parallelism with one another: the improvement comprising the steps of forming pivotal connections between a first set of tie bars and the upper ends of the collector plates while the plates are still outside the gas box; compacting the bar plate assembly by swinging the collector plates toward one another around the aforementioned pivotal connections; transporting the bar plate assembly from a manufacturing station to the gas box location; forming additional pivotal connections between a second set of tie bars and the lower ends of the collector plates while the plates are still outside the gas box; and subsequently moving the assembly into the gas box such that the ends of the tie bars are supported on the aforementioned load-bearing framework.

8. The method of claim 7 wherein the step of forming the first-mentioned pivotal connections comprises the substeps of forming a tubular reinforcement along the upper edge of each collector plate, forming holes at spaced points along each upper tie bar, and locating end portions of the reinforcements in the tie bar holes.

9. The method of claim 7 wherein the step of forming the second mentioned pivotal connections is carried out before the bar plate assembly is transported from the manufacturing station to the gas box location. 

1. In the method of fabricating an electrostatic precipitator of the type which includes a gas box, vertical rows of ionizer wires within the box, and vertical collector plates interposed between the rows of wires: the improvement comprising the steps of tying the collector plates together in a bundle outside the box, said typing step including the substep of forming pivotal connections between each collector plate and tie bars spanning the upper and lower ends of the plates; collapsing the bundle by swinging the plates toward one another around the aforementioned pivotal connections; transporting the collapsed bundle from the bundlemanufacturing point to the gas box location; uncollapsing the bundle; and moving the bundle into a suspended position within the box such that the plates hang vertically in spaced parallelism with one another.
 2. The method of claim 1 and further comprising the step of installing the ionizer wires in the box after the collector plates are in place.
 3. The method of claim 1 wherein the step of moving the bundle into the gas box includes the substep of lowering the bundle through the roof of the gas box.
 4. In the method of fabricating an electrostatic precipitator of the type which includes a load-bearing framework within the upper area of a gas box, spaced parallel collector plates suspended from the framework, and vertical rows of ionizer wires between the plates: the improvement comprising the steps of pivotally attaching two spaced tie bars to the upper ends of the collector plates while the plates are outside the gas box; swinging the plates around the aforementioned pivotal connections such that the plates are collapsed together in a compact bundle; transporting the bundle from a manufacturing station to the gas box location; and subsequently moving the bundle into the gas box to a position such that the upper tie bars are supported by the load-bearing framework.
 5. The method of claim 4 and further comprising the substeps of forming a tubular reinforcement along the upper edge of each collector plate, forming holes at spaced points along each upper tie bar, and locating end portions of the reinforcements in the tie bar holes whereby the upper tie bars are pivotally attached to the plates.
 6. The method of claim 4 and further comprising the step of pivotally attaching two additional tie bars to the lower ends of the collector plates while the plates are outside the gas box; said last-mentiOned step including the substeps of forming a tubular reinforcement along the lower edge of each collector plate, forming holes at spaced points along each lower tie bar, and locating end portions of the reinforcements in the lower tie bar holes so that said lower bars become pivotally attached to the plates.
 7. A method of fabricating an electrostatic precipitator of the type which includes a load-bearing framework within the upper area of a gas box, and collector plates handing from said framework in general parallelism with one another: the improvement comprising the steps of forming pivotal connections between a first set of tie bars and the upper ends of the collector plates while the plates are still outside the gas box; compacting the bar plate assembly by swinging the collector plates toward one another around the aforementioned pivotal connections; transporting the bar plate assembly from a manufacturing station to the gas box location; forming additional pivotal connections between a second set of tie bars and the lower ends of the collector plates while the plates are still outside the gas box; and subsequently moving the assembly into the gas box such that the ends of the tie bars are supported on the aforementioned load-bearing framework.
 8. The method of claim 7 wherein the step of forming the first-mentioned pivotal connections comprises the substeps of forming a tubular reinforcement along the upper edge of each collector plate, forming holes at spaced points along each upper tie bar, and locating end portions of the reinforcements in the tie bar holes.
 9. The method of claim 7 wherein the step of forming the second mentioned pivotal connections is carried out before the bar plate assembly is transported from the manufacturing station to the gas box location. 